1. Field of the Invention
This invention relates to a process of manufacturing a substrate provided with a synthetic resin-bonded friction coating, bonded to the substrate by a primer. The coating is made by compacting a powder mixture containing a friction imparting powder material and a thermosetting synthetic resin powder and curing the compacted powder mixture at an elevated temperature. That process may be used to manufacture elements designed to move in frictional contact with other elements in such mechanisms, as brakes and clutches.
2. Description of the Prior Art
It is known that substrates may be provided with synthetic resin-bonded friction coatings by first preparing a suitable dry powder mixture of a suitable friction imparting powder material and of a binder consisting of a synthetic resin powder and then precompacting the powder mixture to form a compact. The substrate is placed into a metal die, the compact is placed on the substrate, and the compact and the substrate are then molded at an elevated temperature. To join the compact to the substrate, the latter is suitably coated after a sandblasting treatment with a primer, which may consist of an adhesive. After the hot molding, the substrates provided with the friction coating are ejected from the metal mold and are usually placed into furnaces in which the friction coating is cured. After the curing in the furnace, the friction coatings are machined exactly to the desired dimensions. Those known manufacturing processes have the disadvantage that the dry powder mixture must be precompacted because it has a relatively large volume and said compacts cannot conveniently be handled unless they have a minimum thickness so that thin friction coatings, cannot be formed unless the friction coatings are machined after they have been cured. The extent to which the powder mixture is compacted will depend on the pressure applied which control the porosity of the friction coating.